#!/usr/bin/python
# -*- coding: UTF-8 -*-
# 题目：两个变量值互换。
# 程序分析：无

def exchange(a, b):
    a, b = b, a
    return (a, b)

if __name__ == '__main__':
    x = 10
    y = 20
    print 'x = %d,y = %d' % (x, y)
    x, y = exchange(x, y)
    print 'x = %d,y = %d' % (x, y)